“I’m appalled that after approx 50 times flying with my 1-year-old son, ticket counter personnel told me I had to ‘prove’ that he was my son, despite having his passport,” Lindsay Gottlieb, 40, tweeted Monday. “She said because we have different last name. My guess is because he has a different skin color.”

@SouthwestAir I’m appalled that after approx 50 times flying with my 1 year old son, ticket counter personnel told me I had to “prove” that he was my son, despite having his passport. She said because we have different last name. My guess is because he has a different skin color.

The coach, who is white, was about to fly from Denver to Oakland, Calif., on Monday. She was with her son, Jordan, and her husband, who is black, when she was asked to clarify her relationship to the child.

@SouthwestAir she 1st asked for proof with birth certificate. She then said it’s a “federal law” (not true) but asked me to prove I’m mother with Facebook post.What??Mother next to me said she’s never been asked for proof despite diff last name..not shockingly, not mixed face fam

She further tweeted that the experience was “demeaning and insensitive.”

@SouthwestAir it was demeaning and insensitive, not to mention inefficient. Would have missed flight if it was not delayed. I would advise better training for employees to avoid this happening to others

Gottlieb’s story spread on Twitter, causing many to defend the airline’s protocol: “…A friend of mine with her same-race kids makes sure she has all her paperwork in order, whether she is flying domestically or internationally. Don’t think this has anything to do with race…” and “Wow…the employee was doing their job. Making sure that you were not abducting someone’s child. Maybe you should visit the Center for missing and exploited children and hear some of the stories.”

Chrissy Teigen, who shares two biracial children, Luna and Miles, with husband John Legend, tweeted, “Airlines have asked this of me, too, with my daughter. Once I learned it’s a precaution for the very real threat of child trafficking, I stopped being exasperated with it. Now I’m kind of worried when they don’t ask.”

Chrissy Teigen, the wife of John Legend, defended Southwest Airlines after a mom complained she was asked to prove the identity of her biracial son. (Photo: Getty Images)

airlines have asked this of me, too, with my daughter. once I learned it's a precaution for the very real threat of child trafficking, I stopped being exasperated with it. Now I'm kind of worried when they don't ask.

but yeah, it's definitely a situational thing, though. depends on the day, depends on the agent, you never know! going to London is the most difficult with her in my experience. I have to bring a file folder of papers.

In a statement to Yahoo Lifestyle, Gottlieb said, “My family had an interaction with a Southwest Airlines employee last night that was uncomfortable and hurtful. I felt that in this situation, it was my responsibility to say ‘Hey, this isn’t OK.’ We had a passport that verified our son’s age and identity, and both parents were present.”

Gottlieb continued, “But still being pushed further to ‘prove’ that he was my son felt disrespectful and motivated by more than just concern for his well-being. … While it was upsetting and emotional, I realize that this was just one day of my life where I was uncomfortable and our family was made to feel “less than,” whereas others face similar situations on a daily basis. I hope the coverage this has received can serve as a learning opportunity and that all families — regardless of how ‘traditional’ they may or may not look — are treated with dignity and respect.”

Southwest Airlines tells Yahoo Lifestyle it will “Utilize the situation as a coaching opportunity for our employee.” The statement continued, “We apologize if our interaction made this family uncomfortable — that is never our intention. … When traveling domestically, FAA regulations require airlines to verify a lap child is under the age of 2 by reviewing a birth certificate or government-issued identification. Although some international travel requires additional paperwork for leaving the country with a minor, domestic travel does not require airlines to match the last name of a child and guardian.”